I HAVE managed several miles of the River Ure between West Tanfield and Ripon for 50 years.

For the last 20 years, I have been conducting scientific surveys on all the rivers in the Yorkshire Ouse river system for the Environment Agency and Natural England, and I have to take issue with the National Park Notes regarding Himalayan Balsam (D&S Times, Aug 26).

Himalayan Balsam was introduced nearly 200 years ago and is now naturalised on river banks and damp areas.

I challenge its opponents to name one plant or animal that has disappeared in all those years because of it.

On my stretch of river, the balsam was just as prolific 50 years ago as it is today, and in that time we have not lost a single species of native plant. Rare plants, such as Herb Paris and Yellow Star of Bethlehem, are still recorded in good numbers.

Whoever came up with the theory that balsam smothers all other vegetation, leaving bare riverbanks to be eroded by the river, should get out from behind their computer.

Yorkshire Dales rivers have always eroded their banks, and they always will.

Erosion is caused by the velocity of the river in spate.

High rainfall and very efficient land drainage cause bank erosion, not a few puny plants that have hollow stems and virtually no root system.

In December 2015, I was on the Ure’s flood bank at 3am with the river at my feet.

Dead sheep, cattle and even a complete chicken shed came rushing past. The ground was vibrating with the force of huge boulders grinding along the riverbed. Trees were splintering as they were ripped from the ground. This is what causes erosion – not Himalayan Balsam.

According to my studies over the last ten years, balsam is, without doubt, the most important riverbank plant for bumble bees, honey bees, wasps, hoverflies and more than 50 species of other flies. On still, warm mornings, virtually every flowerhead is nodding under the weight of feeding bees.

The insects in turn attract predators like dragonflies, and warbler species such as whitethroat, willow warbler and chiffchaff.

The riverbank would be much poorer ecologically without balsam. The plant may make walking along the riverbank difficult, but it supports more wildlife than any other riverside plant in late summer.

The good thing is that you will never rid the riverbanks of balsam, although I have no problem with removing it in special areas to help certain rare species of plant or insect, like the tansy beetle.

I also ask when has the National Park been the custodian of our rivers? I thought it was the Environment Agency.

With the bee population in free fall, I would have thought that destroying the one plant that is most used by bees in August and September was not the brightest project to promote.

Brian Morland, the Bellflask Ecological Survey Team, East Tanfield, Ripon